KR101115823B1 - Polyester copolymer resin for binder and coating composition comprising the same - Google Patents

Abstract

The present invention relates to a copolyester resin for a binder and a coating composition comprising the same, by introducing a functional group capable of imparting pigment affinity into the polyester resin, thereby improving pigment dispersibility and improving glossiness of a coating film. There is a characteristic. When the coating composition comprising the copolymer polyester resin for binders according to the present invention is applied to the interior of the building, the exterior and the industrial use, such as PCM (Pre-coated Metal), Can (Can) and excellent through the pigment dispersibility improvement Gloss can be expressed.

Binder, Polyester, Paint, Pigment Affinity, Dispersibility

Description

Copolymer polyester resin for binder and coating composition containing same {Polyester copolymer resin for binder and coating composition comprising the same}

The present invention relates to a copolymer copolymer resin and a coating composition comprising the same. More specifically, the present invention relates to a copolymer polyester resin for a binder and a coating composition including the same, which may simultaneously perform a role of a binder and a dispersant by introducing a pigment-friendly group into the copolymer polyester resin.

In the case of industrial paints generally used, paints for applying the interior and exterior of buildings are mainly acrylic emulsions or polyesters as binders, and pigments and other additives are dispersed and mixed in water or container solvents. At this time, the dispersant, which is one of the additives used, serves to prevent the reagglomeration of the pigments dispersed by mechanical force by introducing a pigment affinity group.

Such dispersants have been reported and used in a variety of chemical compositions and molecular weights depending on the type of pigment, that is, inorganic pigments and organic pigments and the pigment itself. However, due to compatibility problems between the dispersant and the resin used as the binder, problems such as phase separation and a sharp increase in viscosity of the coating liquid are caused, and at the same time, the gloss of the final coated film is lowered.

The present invention has been drawn to solve the above problems, it was found that by introducing a pigment affinity group into the polyester binder can improve the pigment dispersibility when applied to the paint, the present invention is completed based on this It became.

Accordingly, an object of the present invention is to provide a copolymer polyester resin for a binder that can perform the role of a binder and a dispersant at the same time by introducing a pigment-friendly group in the molecule.

Another object of the present invention is to provide a coating composition having excellent glossiness by improving the dispersibility of the pigment.

Copolymer polyester resin for a binder according to the present invention for achieving the above object is:

In the copolymerized polyester resin obtained by copolymerizing an acid component and a diol component through an esterification reaction and a polycondensation reaction, the acid component of the copolymerized polyester resin is 1 to 10% by weight of 5-sodiumsulfodimethylisophthalic acid and aspartic acid. It is characterized by containing essentially 1 to 10% by weight.

Coating composition according to the present invention for achieving the above another object is:

It is characterized by including 10 to 35% by weight of the copolymerized polyester resin, 10 to 35% by weight of the pigment and 30 to 80% by weight of the solvent.

Hereinafter, the present invention will be described in more detail.

As described above, according to the present invention, there is provided a copolymer copolymer polyester resin for a binder and a coating composition including the same, which can simultaneously perform a role of a binder and a dispersant by introducing a pigment affinity group into the copolymer polyester resin.

Copolymer polyester resins are prepared by esterification and polycondensation of acid components and diol components, as is known in the art, and in order to verify the effects of the present invention, there is no prior art of having a pigment affinity group. Comparing the respective components of the general-purpose polyester binder and the polyester binder having a pigment affinity group according to the present invention is as follows.

[Universal Polyester Resin]

As acid components of the general-purpose polyester resins according to the prior art, acids such as terephthalic acid, isophthalic acid and adipic acid, diesters such as dimethyl terephthalic acid and dimethyl isophthalic acid, and acid anhydrides such as trimelionic hydride are used.

Ethylene glycol, diethylene glycol, neopentyl glycol, propylene glycol, 2-methyl propanediol, etc. are used as a diol component.

[Polyester Resin Having Pigment Affinity Group of the Present Invention]

The polyester resin according to the present invention essentially contains 5-sodiumsulfodimethylisophthalic acid and aspartic acid as the acid component for the introduction of the pigment affinity group. The amount of 5-sodium sulfodimethylisophthalic acid and aspartic acid introduced into the pigment affinity group is 1 to 10% by weight, preferably 2.5 to 5% by weight, respectively.                     

If the amount of the 5-sodiumsulfodimethylisophthalic acid used is less than 1% by weight, sufficient pigment dispersibility improvement effect cannot be obtained. If the amount of the 5-sodiumsulfodimethylisophthalic acid is less than 1% by weight, the reaction time is delayed and a high molecular weight polyester is hardly obtained.

In addition, when the amount of the aspartic acid used is less than 1% by weight, a sufficient pigment dispersibility improvement effect cannot be obtained. When the amount of the aspartic acid is used in excess of 10% by weight, the reaction time is delayed, and a high molecular weight polyester is hardly obtained.

As the acid component of the polyester resin of the present invention, in addition to the above-mentioned essential components, acids such as terephthalic acid, isophthalic acid, adipic acid and sebacic acid, diesters such as dimethyl terephthalic acid and dimethyl isophthalic acid, trimellitic hydride and the like Although acid anhydride of can be used individually or in combination of 2 or more types, It is not specifically limited to this.

As the diol component of the polyester resin of the present invention, ethylene glycol, diethylene glycol, neopentyl glycol, propylene glycol, 2-methylpropanediol and the like may be used alone or in combination of two or more, but are not particularly limited thereto. .

According to this invention, the coating composition is comprised as follows using the above-mentioned copolymer polyester resin for binders.

Coating Composition

The coating composition which concerns on this invention contains 10-35 weight% of copolymer polyester resins for binders mentioned above, 10-35 weight% of pigments, and 30-80 weight% of solvents.

The binder polyester resin is a polyester resin having a pigment affinity group as described above, and when applied to the paint to improve the dispersibility of the pigment without using additives such as dispersant by simultaneously acting as a binder and dispersant Gives glossiness.

The use amount of the said copolyester resin is 10-35 weight%. In this case, when the amount of the copolyester resin is less than 10% by weight, the adhesion of the paint to the material is insufficient, and when the amount exceeds 35% by weight, the coating is not easy due to the sudden increase in paint occupancy.

The pigment used in the present invention is not particularly limited as long as it is commonly used in the coating composition industry.

The usage-amount of the said pigment is 10-35 weight%. Here, when the amount of the pigment used is less than 10% by weight, the silver penetrating power of the paint is so low that it is impossible to achieve the protection of the original material for coating the paint. A coating liquid with good dispersion can not be obtained.

The solvent used in the present invention is not particularly limited as long as it is commonly used in the coating composition industry.

The usage-amount of the said solvent is 30 to 80 weight%. Here, when the amount of the solvent used is less than 30% by weight, the coating itself is too high to make the coating uniform, and when the amount of the solvent is more than 80% by weight, the coating viscosity is too low to prevent coating over a certain thickness.

As described above, the polyester binder having the pigment-friendly group of the present invention is applied to building paints and PCM and CAN (CAN) paints used in interior and exterior building materials to improve the glossiness of the coating film specimens through the pigment dispersibility.

Although the present invention will be described in more detail with reference to the following examples and comparative examples, the scope of the present invention is not limited thereto.

Examples 1-4

-Synthesis of polyester resin with pigment affinity group

Each component was introduced into the reactor according to the monomer composition shown in Table 1 below. Next, the temperature of the reactor was maintained at 250 ° C and reacted for about 5 hours, and then further reacted at a temperature of 260 ° C under vacuum for about 2 hours to obtain a copolymerized polyester. The obtained copolymerized polyester had an acid value of 0.3 or less, an OH value of 5 to 10, and a number average molecular weight of 12,000 to 15,000.

Herein, the content units of the components shown in Table 1 are in weight percent, and the content units of the components specified in all the tables in the following are expressed in weight percent unless otherwise specified.

division A B C D E F G system Example 1 22 25 13 One One 20 18 100 Example 2 22 25 10 2.5 2.5 20 18 100 Example 3 22 25 5 5 5 20 18 100 Example 4 22 15 5 10 10 20 18 100

A: terephthalic acid

B: isophthalic acid

C: adipic acid

D: 5-sodium sulfodimethylisophthalic acid                     

E: Aspartic Acid

F: Ethylene Glycol

G: neopentyl glycol

Comparative Example 1

-Synthesis of general purpose polyester resin

Copolymer polyester resin was obtained by adding the components in the reactor according to the monomer composition shown in Table 2 and performing the same method as the polyester synthesis method of Example 1. The obtained copolymerized polyester had an acid value of 0.3 or less, an OH value of 5 to 10, and a number average molecular weight of 12,000 to 15,000.

division A B C F G system Comparative Example 1 22 25 15 20 18 100

A: terephthalic acid

B: isophthalic acid

C: adipic acid

F: Ethylene Glycol

G: neopentyl glycol

Examples 5-8

-Paint Solution

The polyesters having the pigment affinity groups prepared in Examples 1 to 4 were used as binders, respectively, and each of the composition components were blended in the ratios shown in Table 3 below, followed by milling with a 3-roll mill to prepare a coating solution. The pigment used at this time was used as DuOnt R-902 Grade as TiO ₂ . The solvent was used by mixing toluene / MEK (methyl ethyl ketone) = 4/6 ratio.

division bookbinder Pigment solvent system Example 1 Example 2 Example 3 Example 4 Example 5 25 - - - 25 50 100 Example 6 - 25 - - 25 50 100 Example 7 - - 25 - 25 50 100 Example 8 - - - 25 25 50 100

Comparative Example 2

A general-purpose polyester having no pigment affinity group prepared in Comparative Example 1 was used as a binder, and the composition was prepared in the same manner as in Example 5 after combining the respective composition components in the ratios shown in Table 4 below to prepare a coating liquid. .

division bookbinder Pigment solvent system Comparative Example 1 Comparative Example 2 25 25 50 100

[Evaluation of Paints Prepared]

The coating liquids prepared in Examples 5 to 8 and Comparative Example 2 were coated with a bar coater on a 0.6 mm EGI steel sheet and dried at 270 ° C. for 50 seconds. The temperature of the actual EGI steel sheet reached at this time was 230 ~ 240 ℃, the thickness of the dried coating film was 23 ~ 28㎛.

Each specimen prepared in this manner was measured 60 ° gloss (Gloss) to confirm the dispersibility of the pigment in the coating liquid, the results are shown in Table 5 below                     

division Example 5 Example 6 Example 7 Example 8 Comparative Example 2 60 ° Glossiness 75 90 92 92 68

In the test results, it was found that the specimen coated with the coating composition prepared using the polyester binder having the pigment affinity group of the present invention has excellent gloss through improved pigment dispersibility. In particular, the proper ratio of 5-sodiumsulfodimethylisophthalic acid and aspartic acid was found to be 2.5 to 5% by weight based on the test results.

As described above, according to the present invention, by using a polyester binder incorporating a pigment-friendly group in the production of paints, the pigment dispersibility by applying to the paints for building and PCM and CAN used in interior and exterior materials without additional dispersant It is possible to improve the gloss of coating film specimens through improvement.

Claims (4)

A coating composition comprising 10-35% by weight of a copolymerized polyester resin for a binder copolymerized through an esterification reaction and a polycondensation reaction of an acid component and a diol component, 10-35% by weight of a pigment, and 30-80% by weight of a solvent. The acid component of the copolyester resin essentially contains 1 to 10% by weight of 5-sodiumsulfodimethylisophthalic acid and 1 to 10% by weight of aspartic acid, The acid component of the copolymerized polyester resin includes terephthalic acid, dimethylisophthalic acid, or a mixture thereof as other acid components other than the 5-sodiumsulfodimethylisophthalic acid and aspartic acid, and as a diol component of the copolymerized polyester resin. A paint composition comprising ethylene glycol. delete delete delete